/Engine/Plugins/Runtime/MassGameplay/Source/MassLOD/Public/MassLODSubsystem.h
typedef TMulticastDelegate_ThreeParams< void, [FMassViewerHandle](API\Plugins\MassLOD\FMassViewerHandle) ViewerHandle, [APlayerController](API\Runtime\Engine\GameFramework\APlayerController) *PlayerController, [FName](API\Runtime\Core\UObject\FName) StreamingSourceName > FOnViewerRemoved